26 



per cent, of the total number of trees may be taken out in the 

 first thinning. In addition to the suppressed trees, poor-shaped, 

 forked, and diseased trees should be taken. 



At the time the first thinning is made about 200 or 250 of the 

 best developed and most promising trees on each acre are se- 

 lected for the final crop. The trees surrounding these selected 

 individuals are not all cut, but are thinned out sufficiently to 

 give the crown of each selected tree a chance to spread slightly. 

 This operation is repeated as often as the space thus provided 

 becomes filled by the growth of the crowns. If this is done 

 carefully, a final stand of 200 or 250 large, well-formed trees is 

 obtained. 



The material obtained from thinnings may be used for fuel, 

 and the trees cut in the later thinnings may even be large enough 

 for fence posts or for railroad ties. In most cases the wood 

 thus obtained should bring more than enough to pay for the cost 

 of cutting the trees, and the benefit to the trees of the main crop 

 is thus obtained free of cost or even at a profit. 



CUTTING THE FOREST. 



Age. 



A forest crop differs from an ordinary agricultural crop in 

 that there is a wide choice in the time when the forest crop may 

 be harvested. Whether a forest is ripe enough to be cut or not 

 is in most cases a purely financial consideration, and not a mat- 

 ter of simple judgment as in the case of a farm crop. The 

 standing trees in the forest may be considered as capital, and 

 the yearly growth of the trees as the interest on the capital. 

 Considered from a purely financial point of view, whenever this 

 growth (or interest) falls below the rate which may be earned 

 by the money into which the timber can be converted, the forest 

 should be cut. Thus, if the trees grow in value at the rate of 6 

 per cent, per year while money is worth 8 per cent., and the trees 

 can be cut and sold, there is a loss entailed in letting the forest 

 grow. This consideration, however, does not definitely deter- 

 mine when the trees should be cut. It simply indicates the age 

 beyond which it is unprofitable to let the forest grow. To find 

 the proper rotation that is, the age at which the trees should 

 be cut, it is necessary to know the value of the tree at different 

 ages, all the items entering into the cost of producing the crop, 

 and the rate of interest demanded on the money invested. This, 

 in turn, involves the construction of yield tables showing the 



